Optical system and projection exposure system

Abstract

An optical system for a projection exposure apparatus, comprises an optical element, a load-bearing structure for carrying the optical element, and an interface coupling the optical element and the load-bearing structure. The interface comprises a first Hirth serration assigned to the optical element. The interface comprises a second Hirth serration assigned to the load-bearing structure. The first Hirth serration and the second Hirth serration mesh in order to define a pose of the optical element in a reference coordinate system.

What is claimed is: 
     
         1 . An optical system, comprising
 a mirror;   a load-bearing structure; and   an interface coupling the mirror and the load-bearing structure,   wherein:
 the interface comprises a first Hirth serration which is assigned to the mirror; 
 the interface comprises a second Hirth serration which is assigned to the load-bearing structure; and 
 the first and second Hirth serrations mesh to define a pose of the mirror in a reference coordinate system. 
   
     
     
         2 . The optical system of  claim 1 , wherein:
 the interface comprises a first serration portion which comprises the first Hirth serration;   the interface comprises a second serration portion comprising the second Hirth serration;   the first serration portion of the interface is connected to the mirror; and   the second serration portion of the interface is connected to the load-bearing structure.   
     
     
         3 . The optical system of  claim 2 , wherein at least one of the following holds:
 the first serration portion comprises first fastening apertures fastening the first serration portion, the first fastening apertures extending through the first serration portion; and   the second serration portion fastening apertures fastening second serration portion, the second fastening apertures extending through the second serration portion.   
     
     
         4 . The optical system of  claim 2 , wherein at least one of the following holds:
 the first serration portion comprises a first central aperture around which the first Hirth serration extends; and   the second serration portion comprises a second central aperture around which the second Hirth serration extends.   
     
     
         5 . The optical system of  claim 2 , wherein at least one of the following holds:
 the first Hirth serration comprises first serration segments alternating with first toothless segments; and   the second Hirth serration comprises second serration segments alternating with second toothless segments.   
     
     
         6 . The optical system of  claim 2 , wherein at least one of the following holds:
 the first serration portion comprises a first spring element carrying a first plurality of teeth; and   the second serration portion comprises a second spring element carrying a second plurality of teeth.   
     
     
         7 . The optical system of  claim 2 , wherein at least one of the following holds:
 the first serration portion comprises a first spring element carrying a first plurality of teeth, and the first spring element extends perpendicular to an axis of symmetry of the interface; and   the second serration portion comprises a second spring element carrying a second plurality of teeth, and the second spring element extends perpendicular to an axis of symmetry of the interface.   
     
     
         8 . The optical system of  claim 2 , wherein at least one of the following holds:
 the first serration portion comprises a first spring element carrying a first plurality of teeth, the first spring element extends perpendicular to an axis of symmetry of the interface, and the first spring element has its lowest stiffness along the axis of symmetry of the interface; and   the second serration portion comprises a second spring element carrying a second plurality of teeth, the second spring element extends perpendicular to an axis of symmetry of the interface and the second spring element has its lowest stiffness along the axis of symmetry of the interface.   
     
     
         9 . The optical system of  claim 2 , wherein:
 the interface comprises a first mirror bushing and a bushing block;   the first mirror bushing is assigned to the mirror;   the first mirror bushing comprises the first serration portion;   the bushing block is assigned to the load-bearing structure; and   the bushing block comprises the second serration portion.   
     
     
         10 . The optical system of  claim 9 , wherein the mirror comprises an optically effective surface and a back side facing away from the optically effective surface, and wherein the mirror bushing is connected to the back side of the mirror. 
     
     
         11 . The optical system of  claim 9 , wherein at least one of the following holds:
 the mirror bushing and the first serration portion define one piece of material; and   the bushing block and second serration portion define one piece of material.   
     
     
         12 . The optical system of  claim 9 , wherein at least one of the following holds:
 the mirror bushing and the first serration portion define multiple pieces; and   the bushing block and second serration portion define multiple pieces.   
     
     
         13 . The optical system of  claim 9 , further comprising second and third mirror bushings connected to the mirror, wherein each of the first, second and third mirror bushings is assigned two degrees of freedom of the mirror. 
     
     
         14 . The optical system of  claim 13 , further comprising first, second and third bipods coupling the mirror to the load-bearing structure via the bushing block, wherein each of the first, second and third mirror bushings is assigned to a corresponding one of the first, second and third bipods. 
     
     
         15 . The optical system of  claim 2 , wherein:
 the first serration portion comprises first fastening apertures fastening the first serration portion, the first fastening apertures extending through the first serration portion; and   the second serration portion fastening apertures fastening second serration portion, the second fastening apertures extending through the second serration portion.   
     
     
         16 . The optical system of  claim 15 , wherein:
 the first serration portion comprises a first central aperture around which the first Hirth serration extends; and   the second serration portion comprises a second central aperture around which the second Hirth serration extends.   
     
     
         17 . The optical system of  claim 16 , wherein:
 the first Hirth serration comprises first serration segments alternating with first toothless segments; and   the second Hirth serration comprises second serration segments alternating with second toothless segments.   
     
     
         18 . The optical system of  claim 17 , wherein:
 the first serration portion comprises a first spring element carrying a first plurality of teeth; and   the second serration portion comprises a second spring element carrying a second plurality of teeth.   
     
     
         19 . The optical system of  claim 1 , wherein the mirror comprises an optical waveguide and a fiber connector carrying the optical waveguide, wherein the first Hirth serration is on the fiber connector. 
     
     
         20 . An apparatus, comprising:
 an optical system according to  claim 1 ,   wherein the apparatus is a projection exposure apparatus.